Application of an ortho-Formylation Reaction in One-pot Procedures and Natural Product Syntheses

Abstract

This thesis describes the transformation of phenols into ortho-hydroxycinnamates, salicylamines, benzoxazines, and salicylnitriles in good overall yields by simple, regioselective, and one-pot procedures using a combination of MgCl2-Et3N as a base system. These one-pot processes are more economically and environmentally benign than those methods previously reported. The MgCl2-Et3N base system was also used in a regioselective Mannich reaction.<br> Moreover, the first total synthesis of (±)-powelline was described in 10% overall yield over eight steps using an ortho-formylation reaction and an intramolecular oxidative phenolic coupling reaction as the key reactions. The first total synthesis of the naturally occurring all-(Z)-5,7-dihydroxy-2-(4,7,10,13,16-nonadecapentaenyl)chromone was also achieved in six steps from the ethyl ester of eicosapentaenoic acid with an overall of 14% yield.